I'm not fat!

One of my favorite lines to tell people when my weight comes up is "I'm not fat! I'm fluffy!" (thanks Miss Lime). But the truth is, I do need to loose some pounds. And I've been trying. My health is relitivly good, need to work on the trigs, but other than that, docotrs arn't too worried about it. But I have been trying.
My plan was, before the babino, to go on a bike ride on the trail by our hous after work at Cookies. That got blown out of the water.
I'm also having a hard time movin' and shakin' it recently because I'm just so tired! I was like this with Sean, where all the energy I have is just sucked out by the growing baby. That's how he got his nick-name.
Does anyone have ay advice on how do get some exercise in when I'm tired and preggo? Help?